. "The power of regulating commerce extends to the regulation of navigation. The power to regulate commerce extends to every species of commercial intercourse between the United States and foreiga nations, and among the several States. It dees not stop at the external boundary of a State.
But it does not extend to a commerce which is completely internal. The power to regulate commerce is general, and has no limitations but such as are prescribed in the constitution itself. The power to regulate commerce, so far as it extends, is exclusively vested in Congress, and no part of it can be exercised by a State.
State inspection laws, health laws, and laws for regulating the internal commerce of a State, and those which respect turnpike roads, ferries, &c. are not within the power granted to Congress."
U.S. Supreme Court
GIBBONS v. OGDEN, 22 U.S. 1 (1824)
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